Hydraulic motor and/or pump mechanism



June 1o, 1958 L F JOY 2,838,003

HYDRAULIC MOTOR AND/OR PUMP MECHANISM Original Filed Jan. 21, 1947 5 Sheets-Sheet 1 lzvenor:

June 10, 1958 J. F. JOY

HYDRAULIC MOTOR AND/OR PUMP MECHANISM Original Filed Jan. 21, 1947 5 Sheets-Sheet 2 June l0, 1958 J. F. JOY

1 2,838,003 HYDRAULIC MOTOR AND/OR PUMP MECHANISM Original Filed Jan. 21, 1947 5 Sheets-Sheet 3 June l0, 1958 J. F. JOY 2,838,003

y HYDRAULIC MOTOR AND/OR PUMP MECHANISM Original Filed Jan. 21, 1947 5 Sheets-Sheet 4 77 77 lzvevzor: 7056/1972, E 0y.

June 1o, 1958 J. F. JOY 2,838,003

HYDRAULIC MOTOR AND/OR PUMP 4MECHNISM Original Filed Jan. 21, 1947 5 Sheets-Sheet 5 lllll-Ill'llllllllllIllllllllll lllllil'llllllllllllllllllllllll United lld ,Patented June l0, 195

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HYDRAULIC MTOR AND/ R PUD/EP l/ECI-IANISM Joseph F. Joy, Pittsburgh, Pa.

Original application `lianuary 21, 1947, Serial No. 723,436,

Divided and this application September Ztl, 1952, Serial No. 310,5@

4 Ciams. (Cl. 10S-4) This invention relates to hydraulic mechanisms and more particularly, but not exclusively, to hydraulic pressure generators -or motors together with improved control means therefor. v

Hydraulic pressure generators or motors of known types usually operate at relatively low speeds and usually embody auxiliary mechanisms such as secondary priming pumps, resulting in structures which are not only excessively complicated but which also result in additional power losses. Moreover, single units of such known types'are usually'incapable of operation selectively either as a pressure generator or as a motor without substantial change in parts or additions thereto. In such pressure generators or motors, there is danger, if operated at unusually high speed, of causing voidslin the uid cavitywhich reduces the responsiveness of the hydraulic column, resulting in substantial power losses. Further, in such known mechanisms, when operated at relatively high speeds, there is danger of substantial overheating as a result ofthe operation of the mechanism due to lack of adequate cooling means in the fluid system. Further in such known mechanisms, flexibility of operation and simplicity of construction and the desired high degree to responsiveness to controls are lacking, and due to their relatively complicated construction, are not only relatively cumbersome and heavy but are also relatively costly to manufacture. Further, because of the great number of parts heretofore common to such'mechanisms and the high degree of accuracy essential to the proper coordination and functioning of so many parts in such a mechanism, only highly skilled artisans are permissible for their manufacture, installation, careand operation. By comparison with such known mechanisms, the present invention will be found to embody much fewer parts, all of simple character, and the more important members of which are standard products with leading ball and roller bearing manufacturers. Another serious weakness of other or reservoir serving the hydraulic system. In the present invention. the improved pressure generator or pump is well adapted for use in high speed operation and is enl tirely capable of meeting relatively severe demands of known mechanisms which prevents their successful use i for the applications comtemplated by the present invention is the great number of pressure-tight joints that must be maintained leak-tight under conditions of great vibration and shock. In the present invention, all high pressure conduits are internal of the mechanism, whereby absolute sealing becomes unnecessary and the outer enclosures are only required to confine they slight leakages which occur within, and means are provided for returning such leakage back into the lluid column forming the hydraulic medium. It has been common practice with known types of pressure generators and motors to provide 'special drain lines connected between theV interior or operating cavities of such mechanisms and the sump service which call for a usually high degree of responsiveness to controls and eiliciency in operation, and is simple in construction, relatively light in weight, may beV produced at relatively low cost, and by the provision of interchangeability of component parts, the cost of replacement and repair is relatively low.

It is accordingly a principal object of the present invention to provide a hydraulic mechanism which may be operated eciently at relatively high speeds and which possesses a minimum of weight consistent with great durability, high eliiciency, ease of application and operation, and highly responsive to the controls thereof. A further object is to provide an improved hydraulic mechanism which may be employed as either a pressure generatorv or a motor. Another object of the invention is to provide an improved hydraulic mechanism having improved control means whereby displacement may be readilyv varied. A further object is to provide an improved hydraulic pressure generator or motor embodying improved cooling means for the fluid system. A still further object is to provide an improved hydraulic mechanism which is relatively simple in design and construction and wherein wear due to friction is reduced to a minimum. Another object is to provide a hydraulic mechanism capable of use as either a pressure generator or fluid motor without change in its component parts or additions thereto whatsoever. Yet another object is to provide an improved hydraulic mechanism wherein a variationin displacement and reversal may be readily eiected. A further object is to provide an improved pressure generator or motor which is embodied in a unitary mechanism and providing for wide variations between input and output speeds and torques by means of highly responsive controls capable of both manual and automatic operation. Another object is to provide an improved hydraulic mechanism embodying improved means for the salvaging of all leakage and the return of the same to the intake ports of the hydraulic fluid column, thus completely eliminating the need of external drain lines common to such mechanisms. These and other objects of the invention will, however, become more apparent in the course of the following description and as more particularly pointed out in the appended claims.

This application is a division of my copending application Serial No. 723,436, iiled January 2l, 1947, now matured into Patent No. 2,646,755, dated July 28, 1953.

In the accompanying drawings there are shown for purposes of illustration different embodiments which the invention may assume in practice.

In these drawings:

Fig. l is a cross-sectional view of an illustrative embodiment of the invention, showing means for varying the displacement of the mechanism.

Fig. 2 is a vertical sectional view, with parts shown in full, illustrating manually operable means for controlling the variable displacement mechanism disclosed in Fig. l.

Fig. 3 is a vertical sectional view, with parts shown in full, taken substantially on line 3-3 of Fig. 2.

Fig. 4 is a central longitudinal vertical sectional view v ci? showing a modified embodiment of the invention arranged for use as a pressure uid generator.

Fig. is a central longitudinal vertical sectional view of a similar embodiment of the invention which is remotely connected to the pressure generator, shown in Fig. 4, to operate as a motor.

Fig. 6 is a central longitudinal vertical sectional view showing the mechanisms of Figs. 4 and 5 assembled into a unitary hydraulic mechanism.

Fig. 7 is a plan view illustrating another embodiment of the invention which is provided with a system of controls for'regulating the speed and displacement.

Fig. 8 is an end elevational view` of the mechanism shown in Fig. 7.

Fig. 9 is a cross-sectional view taken substantially on line 9 9 of Fig. 7, illustrating the variable displacement pressure generator.

Fig. l0 is a View in central longitudinal vertical section taken through another embodiment of the invention and incorporating means for cooling the hydraulic operatingiluid. .fr

Fig; llris. an elevational View of the mechanism shown in Figivv l0, 'withparts shown in vertical section to illustrate structural details.

The pressure generator or pump, shown in Fig. l and in part shown in axial section in Fig. 4, may be similar to that disclosed in my copending application Serial No. 723,436 above referred to and may include a casing 1, a stationary shaft or pintle 2, a rotor 3 and a cam track 4all as shown in Fig. l. As shown in Fig. 4, the rotor is journaled yfor rotation within the casing in coaxial relation with the stationary pintle 2 and has formed therein radially located cylinder bores which contain reciprocable ball type pistons 6. The cylinder bores have ports 7 which are communicable with valve cavities 8 and 9 in the pintle as the rotor revolves and these valve cavities communicate with longitudinal ducts which are in turn 'communicable with either a source of liquid under pressure and a suitable point of discharge or pressure utilization. A suitable shaft, shown in Fig. 4, is connected to the rotor and may serve either as a drive or driven shaft depending upon the manner of operation of the mechanism. The cam track may comprise a conventional roller bearing having inner and outer races 12 and 13 for guiding interposed rollers 14. In this construction, the casing 1 has a chamber or cam track bore 15 which is laterally enlarged and arranged to permit the cam track 4 to move laterally to and `fro across the axis of the-rotor'for the purpose of regulating the volumetric ydisplacement and `the direction of fluid ilow when the mechanism is employed as a hydraulic pressure generator and the regulation of speed 'and direction of rotation -whenf'the mechanism is operated as a hydraulic motor. The outer'raceway of the cam track bearing is herein supported at its top and bottom by hardened inserts or buttons 16 which are employed to guide the cam track during lateral adjustment thereof thereby to overcome excessive Wear of the walls of the bore of the casing at the points where the shiftable cam track has contact therewith. A still added advantage of this construction is that it permits all of the portions of the casing-to be brought into alinement with each setting of the parts. Lateral movement of the cam track is accomplished by a manually operable control device shown in Figs. 2 and 3, comprising cylinders 18 and 19 which are respectively connected Iby conduits 20 and 21 to cylinders V2.2 and 23 secured to the casing of the mechanism (see Fig. l). Y The cylinders V18 and 19 respectively contain reciprocable pistons 24 `and 25 while the cylinders 22 and 23 respectivelycontain reciprocable pistons 26 and 27. rl`hese cylinders and conduits are lled with a fluid medium, preferably a light lubricating oil, through illing and purging plugs 2-8, 29, 30 and A31 which are preferablyconventional-high pressure, ball valve, oil ttings. A conventional high pressure oil gun, such as is used for automobile lubrication, may be used lfor filling the iluid system. All air should be purged from the closed system by depressing the ball valve of the fitting at the opposite end of the system, from where oil is being pumped until air ceases to ilow past the depressed ball. After the system is completely purged, it should be under sufficient hydraulic pressure to cause the desired solidity of the hydraulic column necessary for responsiveness of movement between the actuating cylinders 18 and 19 of the control device of Fig. 2 and the corresponding actuated pistons of the cylinders 22 and 23 of Fig. l. As the aforementioned hydraulic column is being established, the system should be adjusted to cause the axis of the cam track 4 to coincide with the axis of the rotor 3 and a pointer 32 on a control arm 33 to rest at zero on an indicating segment 34. The pointer 32 is formed on each side of the base of a sleeve 35 secured to the control arm and arranged to be locked in any position by being clamped to the indicating segments by means of a threaded knob 36 at the upper end of the control arm, such locking being effected by screwing down the knob on the threaded end 37 of the control arm. It will thus be made clear that actuation of the pistons 24 and 25 of the control device of Fig. 2 causes a corresponding movementof the pistons 26 and 27 which bear against the outer member 13 of the antifriction bearing which Vsupports the cam track 4. It is further obvious that the cam track 4'can thereby be laterally-moved within the casing chamber 15 to or fro across the axis of the rotor 3 for the purpose of varying the volumetric displacement of the rotorat any5desire`d amount between that of zero and a maximum. Such movement will cause a reversal uid flow-with a given-direction of rotor rotation or a reversal of rotor rotation with a given direction of fluid ow, thusyielding complete control of the operation of the mechanismwhether use d as ailuid pressure generator or as a mechanism' for the conversion of fluid pressure into rotary motion.

In Figs. 4 and 5 there is shown a modiiicatiomwherein two of the hydraulic mechanisms, generally designated 40 and 41 respectively, may lbe remotely connected by a closed hydraulic uid circuit for use as a power transrnitting medium. The internal construction of this mechanism may embody constant displacement features similar to those of the mechanism shown in Figs. l and 2 of the application above referred to or the variable displacement characteristics similar to those shown herein in Fig. l and provided with manual control means similar to that shown in Figs. 2 and 3, or the combined manual and automatic control means of certain of thc other .embodiments of the invention to -be later described.

'In this novel arrangement, either of theunits 40 and 41 may be used as the driven or driving mechanism, so long yas a liquid tank 42 is connected to the intake side of the driven unit. Assuming the unit 40 in Fig. 4 to be the driven unit, and rotation is imparted Vto Vits rotor 3 by means of an outside source of power in one direction,

the cam track 4', Iwhichmay correspond to the cam track shown in Fig.,l, would be moved laterally in one direction, thus causing ducts 10 and 11 in a valve pintle 2', similar to the pintle 2 shown in Fig. l, respectively toy become the uid intake and discharge. In the case of reverse rotation, movement of the cam track 4' laterally in the opposite direction would cause the duct 11 to become the fluid intake and the duct 10 the uid discharge. The exibility of the variable displacement feature of the construction shown in Fig. l in connection with a pressure lgeneratoris thus indicated. `With the mechanism shown in Fig. 4 operating lasa pressure generator, it will be notedpthat uid under pressure will be "supplied throughan external pressure :conduitv46 to an Ainternal pressure duct 47 of the mechanism 41 Ashown in Fig. 5*, and then the latter mechanism will function to convert the uid pressure generated by the mechanism 40 (Fig. 4) into 'rotary motion to lbe transmitted through las the result of internal leakage.

spasms its output shaft 48 toperform useful work. "Ehe speed of rotation Vof .the output shaft will depend upon the displacement of both units 40 and y41 or'either that of the pressure generating unit 40 or that lof 4the output unit 41, while the direction .of rotation ofthe output shaft 48 is dependent upon which side of the axis .of the rotor 49 (Fig. 5), the cam track 50, which is :similar .to the cam track shown in Fig. 1, is moved to. `For instance, l

as the cam track 50 is moved laterally in one direction to one side of the rotor axis, 'the rotation of the output shaft 48 would :be in one direction, and likewise movement of the cam track `to the opposite side `of the rotor axis would `result in reverse lrotation yof the output shaft. In either case, and regardless ofthe direction ofzrotation, cylinder filling would take place during fthe lower half revolution, and cylinder `discharge would take place .during the top half revolution in fthemanner described above in regard to the embodiment shown `in Fig. ;1,'through `an rinternal duct 5i (Fig. 5) from where it would :be conducted to the liquid tank 42 through external conduit S2. As has been previously sstated, `the power 'transmission rarrangement shown in Figs. 4rand .5 operates on :a closed pressure vsystem in connection with which the itank 42 functionsas both a reservoir for the .oil forming vthe hydraulic medium and as :an :air chamber. The size of the tank 42 is dependent upon nthe amount of fluid pressure generated as a result .of operation, :but yin the present instance is intended only for light .loads 'and infrequent operation, and when the mechanism is employed for heavier service, a cooling system, -such :as `will be .herein later described, may be substituted :for this tank. The hydraulic fluid system should The completely ifilled except for a small cavity at the top of the liquid' tank A42 which should be provided for air space and lexpansion of the oil as the result of the increased temperatur-e which can be expected to arise out of operation. -For operation at relatively high speed, Zit has been found vbeneficial from the standpoint of cylinder filling, particularly as regarding the pressure generator or pumping lend `#(Fig. 4L), to apply yair or gaseous pressure on' top Iof the -oil in the tank 42. Avn air or gaseous fluid-pump 53 isfprovided for that .purpose and may be-of the type commonly used for pumping air into blow torches andlpneumatic tires. The air cushion thus provided under pressure, res-ting upon the hydraulic oil column, tends to 'solidify the oil column conducive to complete-'cylinder Vfilling.".permit-ting the luse of smaller conduits yand also serves `to absorb any Vibration and shocks common tothe hydraulic `fluid -column of all similar mechanisms. l`Since one of the -principal objects of the invention 4is the #securement-of lmarii mum `power with a lminimum Iof weightjhigh speed of operation is obviously the greatest contributing factor thereto. It has 4heretofore been Enecessary to loperate previous mechanisms of the present vtype at-xelati'vely low speeds, and Y'the chief reason for such low speed operation in previous mechanisms, aside from balancingvdifficulties, has been incomplete cylinder ifilling. "Do lovercome this, vauxiliary pumps have been commonly used to supply duid under pressure to :the 5inta`=ke side of such pressure generators `or pumps. `Such a system, 'while effective for the purpose, has the .disadvantages of creased weight, additional complications '.'to what is usually an already complicated mechanism, :and l,greater mechanical losses.

In order to insure `com-plete cylinder dlling at extremely high speed operation, in addition tothe air pressure loaded hydraulic oil column, there is .provided a scavenger pump located in 'the interior of ythe rotor. The

Yfunction of the scavenger pump ispto "eliminate resistance to the outward movement tof the ball-'like'pistons :6 by the filling ofthe casing chamber -54 .'(Fig. 141) with illuid The scavenger pump consists of a -piston V:55 reciprocably mounted in a cylinder 56 formed internallyv of the v`shaft-extension 45-7 of "the rotor '3'. The piston TSS is provided with a radially 6 disposed `cam track 58 which `engages a pin 59 secured Vto the `rotor 3. The piston TS5 yis provided with a cross slot 60 at the end thereof opposite from the cam track 58, and this slot .60 engages a rectangular-shaped-extension 61 formed on the inner end of the valve pintle 2. The cross slot 460, coacting with the rectangular-shaped extension 61 of the pintle 2', while preventing rotation of the piston 55 in the cylinder 56, permits longitudinal movement of the-piston, thereby. causing the piston to move back and forth in the cylinder as a result of the cam track 5S engaging the pin 59 as the rotor 3' revolves. As the piston 5S moves vaxially outwardly of the cylinder .56, a partial vacuum is created at its inner lend, causing any oil that has accumulated in excess amount in the casing chamber 54 to .flow into the cylinder 56 through `a port 63 in the shaft 57. Upon the return or inward stroke of the piston 55, the oil is trapped in the cylinder 55 through the closing of .a valve 64 and discharges through Aa valve 65 into the cross slot 6i), from where it is free to flow into the then intake duct 10 or 11 `by reason olf the rectangular extension 61 being less in width than the cross Vslot-60. A similar scavenger pump, generally designated 66, is provided in the output uni-t 41 for removing excess oil leakage from the casing chamber 67. The structural 'features of these scavenger pumps are illustrated on an enlarged scale in Fig. 6 and similar parts are designed by similar `but primed numerals therein. In operation, these scavenger pumps serve to maintain a partial vacuum in the casing chambers 54 and V67, thus assisting in effecting outward movement of the ball-like pistons and greatly contributing to the complete filling of the cylinder at high speed operation. Furthermore, it is a well known fact that great heat arises out of the high speed operation of such mechanisms with the casing chambers completely filled with oil. Therefore, the scavenger pumps perform a very useful purpose, regardless of whether the `mechanism is used as .a pressure generator or a `lpressure motor by removing internal leakage as it occurs without 4the use of special outside drain lines.

.In the modification shown in Fig. 6, the two mechanisms shown in Figs. 4 `and 5 are assembled into a unitary hydraulic mechanism with the pressure generator generally designated 40 and the output -unit generally designated 41 secured together by a common pintle 68. Obviously since both ends of this assembly are alike in character either end may be used as the pressure ygenerator and the other the output unit depending -upon demand requirements. In this construction, the two units are arranged in adjacency with the liquid tank 42', mounted directly at the tops thereof. The ducts -11 and 47, in this construction, are combined into a single yduct 69 inthe .commonpintle 68, while the ducts 10 and 51 are .both formed in the common .pintle 68 and are connected through passages 70 vand 71, respectively formed in the casings of the units and communicating directly with the tank 42. The scavenger pump of the pressure generator unit 46 has its piston 55' connected directly with a rectangular extension 61 to the adjacent end of the common pintle 68, while the piston of the scavenger pump of the voutput unit 41' is similarly .connected with the opposite end of the pintle. Otherwise, this unitary mechanism 'embodies the same features ,of con-struction and principles of operation as have vbeen heretofore described in connection-with Fig. l and more particularly with Figs. 4 and 5.

In the modified embodiment of the invention shown in Figs. 7, 8 and 9, vthere is provided an improved system of controls for the regulation of the speed and displacement `of the pressure generator and output mechanisms. These controls differ somewhat from the control means provided for manual operation and disclosed in Figs. l, 2 and 3 rin that they are attached to and form an integral part ofeach mechanism, as generally designa-ted 75 `and 176 `in Fig. 9. They consist, in ithelmain, ef

vspring loaded pressure responsive devices acting against opposite sides of the cam track 4' which is similar to the cam track shown in Fig. 1, for the purpose of automatically controlling the volumetric output of pressure generation and the speed ofthe pressure motor within the desired ranges. Provisions are also made for the manual adjustment of these characeristics where constant volumes and speeds are desired. By referring to Fig. 9, it willbe seen that the spring loaded device 75 consists of Va spring 77 enclosed within a plunger 78 for operation within a cylinder 79 attached to the casing 80 of the output unit. The spring 77 urges the plunger 7S inwardly and serves to exert a predetermined pressure through the plunger 78 against the outer race 13 of a cam track bearing 14'; and plunger 78 is forced outwardly, as the spring pressure is overcome, by pressure acting against the opposite side of the cam track. The Outer end of the spring 77 bears against the head of a pin 83. At the opposite side of the mechanism is the spring loaded device 76, arranged to counteract the spring pressure of the opposed device 75 just described, and comprises a piston 84 arranged for longitudinal movement in a cylinder 85 and which exerts its pressure against the outer race 13' of the cam track bearing at` the side thereof opposite from the plunger 78. The cylinder 85 is connected to the pressure duct of the mechanism through a valve 86, conduit 87 shown in Fig. 7, and connection 88 shown in Fig. 6. The piston 84 therefore becomes responsive to whatever pressure exists in the uid column. Fig. 9 depicts the motor or output end of a power transmission and, as shown, indicates operation at maximum piston stroke, a condition yielding maximum torque and minimum speed of rotation for a given fluid input. the mechanism is reduced, the pressure is reduced on the piston 84 under which condition the spring 77 reacts to move the cam track 4 toward the axis of the rotor 89, thus shortening the piston stroke and increasing the rotor speed. The foregoing assumes a constant uid input; however, the same control devices shown in Fig. 9 may be applied in reverse order to the pressure generator end of the power unit to likewise act, except in the reverse order, to decrease the volumetric displacement of the generator as theV result of increased pressure on the control piston. In other words, the control devices are interchangeable with each other for the purpose of coordinating the direction of fluid flow with the direction of desired rotation, and are also interchangeable between units to permit of wide variations of speed of the output shaft with that of the input shaft by an infinite number of stepsbetween that of zero and that of high overdrive, all of which is automatically regulated so as to avoid output demands exceeding or overloading the driving medium connected to the input shaft.

In addition to the aforedescribed automatic controls, there is also provided means for effecting manual control whereby the cam tracks of the mechanism may be moved to and locked in any desired position of adjustment for effecting control of the volumetric displacement, the direction of fluid flow of the pressure generator and the direction of speed of rotation of the output shaft. This improved manual control consists of a threaded stem .or screw 90 threaded within a plug 91 attached to the spring cylinder 79 and which is arranged to be adjusted against the spring pin 83 as by a knob 92 secured to the stem. The control device 76, at the opposite side of the cam track, includes a threaded stem or screw 93 which is threaded within a plug 94 attached to the cylinder 85, and this stem is arranged to lbe screwed inwardly and bear against the stem of the piston 84 as by a knob 95 -screwed to the stem. Obviously, by screwing the stem 90 of the control device 75 inwardly, the outer race 13 of the cam track can be caused to move across the axis of the rotor 89 to the opposite side of the cam-track-p.

Obviously, as Lthe load imposed on CJI - crosswise of the radiator base.

".bore 96, thereby resulting in opposite rotation of the result of being rmly clamped between the screws and 93. It is further .obvious that the manual adjustment may be used in combination with the aforedescribed automatic controls as a means for limiting the range of automatic control in either or both the input or output ends of the mechanism as may become desirable under certain operating requirements. It is also clear that in the simple system of control provided, a standard mechanism may be caused to operate so that the input end has a constant displacement while the output end is automatically variable or vice versa, or both ends may have either constant or variable displacement as may be desired. In order to make displacement adjustments accurately, there are provided pointers 97 attached to the control cylinders and indicating on micrometer graduations 98 onthe operating knobs which indicate by an infinite number of steps the exact percentage of displacement delivered by a given setting of the indicator.

In the modied embodiment shown in Figs. 10 and 1l, there is shown a unitary hydraulic power transmission, generally similar to that shown in Fig. 6, and including provisions for cooling the oil column. This embodiment includes the same general means for manual and automatic control, as has been heretofore described in connection with Figs. 7, 8 and 9. In Fig. l0 it will be noted that both the input and output mechanisms are enclosed within a single casing 100 in lieu of the separate casings shown in Fig. 6, and this single casing is closed at its ends by heads 101 and 102 which may be interchangeable with each other. This feature of interchangeability may also apply to all other parts forming the mechanism, thus contributing much to the lowering of the cost of pro- Y duction and simplification of assembly and repair. Since both ends of the mechanism are duplicates, either end may be connected to the driving medium and either end may be the pressure generator end while the other end may be the output end. As in the embodiment shown in Fig. 6, there is a common pintle 103 connected between the rotors of the two units. For purposes of explanation, it will be assumed that the driving medium, as for example a driving motor, is connected to a coupling 104. In this case, a duct 105 in the pintle may be the uid inlet to the pressure generator, and the duct 106 inthe pintle may be the fluid discharge. The duct 106 extends through the valve pintle 103 to the motor end of the mechanism, thereby causing the pressure of the generator or input end to act directly against the ball-like pistons of the motor or output end, and thus imparting motion thereto and with the motor and discharging its uid back into the duct 105. The duct 105 has a partition 107 inserted in a conduit 10S and intersecting the duct 105 centrally to block the latter so as to cause the fluid discharge from the motor into the duct 105 at one side of the partition to rise up along one side of the conduit 108 into the improved cooling system generally designated 109, herein mounted at cooling system 109 consists of a radiator 110 and a fan 111 carried by a shaft 112 and provided with a pulley `113 and a driving belt 114 arranged to be driven by a pulley 115 integral with the coupling 104. The radiator has cavities 116 and 117 formed in the extending The cavities 116 and 117 connect at the centers thereof with the conduit 108 but are separated from each other by the partition 107. Another cavity 118 is formed across the top of the radiator 110. Two sets of vertical radiator tubes v are provided to complete the uid circuit through the radiator; one set of which, as indicated at 119, connects between cavity 116 at the base of the radiator and the assuma -9 cavity 118 at the top thereof, and the "other set of 'tubes 12d connects between the top cavity 118 andthe bottom kcavity 117. A pump 121 is provided in the top cavity 118 A-for the purpose of applying the necessary air pressure to the oil column to cause cylinder filling on the generator side under conditions of .high speed operation. A pressure gauge 122 is provided topermit the establishment of the desired pressure and to indicate any change thereof. A filling cap 123 is provided for convenience in charging the hydraulic fluid column of the mechanism. The system should be preferably charged with liquid to approximately the top of the pump 121 and the vremainder of the radiator cavity 118 be left as an air chamber.

As a result of this invention, an improved hydraulic mechanisms is provided which may be operated elliciently at relatively high speeds and which is not only highly elllcient and may be easily applied and operated and also highly responsive to the controls thereof but is also yof relatively low weight, compact and relatively durable,

well adapted to meet the demands of service encountered.

The improved hydraulic mechanism, in certain of its embodiments, may be operated either as a pressure generator or a pressure motor, and by the provision of the improved control means in certain embodiments, the displacement of the mechanism may be readily varied.

Further, by the provision of the improved construction of the hydraulic mechanism and the improved control means associated therewith, variation of displacement and reversal may be readily effected. By the provision of the improved scavenger pump arrangement, all leakage of fluid may be salvaged and returned to the hpdraulic fluid column. Obviously, the need of special drain lines to care for leakage is eliminated. Cooling is'improved by the provision of the novel radiator arrangement. By the provision of the improved rotor and cylinder arrangement and the ball-like pistons engaging shiftable cam tracks formed on the inner races of antifriction bearings, friction and resultant wear is reduced to a minimum. Other uses and -advantages of the invention will be clearly apparent to those skilled in the art.

While there are in this application specifically described several embodiments which the invention may assume in practice, it will -be understood that these embodiments are shown for purposes of illustration and that the invention may be further modified and embodied in various other forms without departing from its spirit or the scope of the appended claims. v

What I claim as new and desire to secure by Letters Patent is:

1. In a hydraulic mechanism, a casing having a chamber, a hydraulic device from which iluid leakage may occur including rotor means mounted for rotary motion Within said chamber, said chamber being constructed to receive fluid leakage from said hydraulic device, a

scavenger pump for pumping fluid from said chamber and having scavenger pump elements contained within said rotor means including cylinder means extending along and coaxial with the axis of said rotor means, said cylinder means being rotatable with said rotor means, a piston contained in said cylinder means, casing mounted means cooperating by a sliding interlock connection with said piston to prevent piston rotation and limit piston motion to reciprocating motion along the axis of said cylinder means and said rotor means, means for driving said piston in reciprocating motion by reaction between said casing mounted means and said rotor means during rotation of said rotor means, said scavenger pump including passage means providing fluid communication from said chamber to said scavenger pump for conducting fluid from said chamber to said scavenger pump, said passage means including an opening through said rotor means from the exterior thereof to said scavenger pump and a valve carried by said rotor means constructed to limit fluid flow through said opening for one way fluid flow to said scavenger pump, uid discharge passage means fromsaid scavenger pump for discharging fluid pumped by said scavenger pump to a suitable point of delivery, 4said fluid discharge passage means including an opening through a pumping element of said scavenger pump and a valve carried by the same pumping element constructed to limit fluid flow through said opening for one way fluid flow from said scavenger pump.

2. In a hydraulic mechanism a casing having a chamber, a hydraulic device comprising rotor means mounted for rotary motion within said chamber, a pintle opening in said rotor means extending along and concentric with the axis of lrotation of said rotor means, a pintle fixed to said casing, said pintle projecting into said pintle opening, multiple fluid passages in said pintle, said multiple fluid passages including fluid passage intake means to and fluid passage outlet means from said hydraulic device, openings within said rotor means, said rotor means and said pintle being constructed to provide that rotation of said rotor means brings said openings within the rotor means into alternate successive fluid communication respectively with said fluid passage intake means and` lluid passage outlet means, said chamber being constructed to retain internally fluid leakage from said hydraulic device, a scavenger pump including a cylinder chamber with a piston and a cylinder, said cylinder comprising a cylinder bore extended from said pintle opening and ending with a cylinder head in said rotor means, said cylinder bore extending along and concentric with the axis of said rotor means, said piston being axially movable within said cylinder bore, an extension from said pintle extending into said cylinder bore, a recess provided in said piston, said recess coacting with said pintle extension to confine movement of said piston to longitudinal movement in said cylinder bore, piston drive means driven by rotation of said rotor and constructed to impart reciprocating motion to said piston longitudinally along the axis of said cylinder, lluid passage means from said chamber extended through said rotor means to the cylinder chamber of said scavenger pump, fluid passage means from said scavenger pump, valve means in said lluid passage means for one way fluid flow into and fluid discharge from said scavenger pump, said scavenger pump being constructed to pump from said chamber fluid having leaked from said openings in the rotor means during rotation of said rotor means.

3. In a hydraulic mechanism as set forth in claim 2, space between the end of said pintle opening and said pintle, a connective passage providing fluid communication between said space and one of said multiple fluid passages in said pintle, said pintle extension being constructed for suflicient play in said piston recess to provide for fluid flow from said piston recess to said space and said fluid passage means from said scavenger pumpv including an opening through said piston from the cylinder chamber to said piston recess with valve means in said opening through the piston and including the piston recess and the space between said pintle extension and the piston recess, the said space between the end of said pintle opening and the pintle and the said passage from said space to one of said multiple iluid passages.

4. In a hydraulic mechanism as set forth in claim 2,

f said fluid passage means from said chamber including an 'opening through said rotor from the exterior thereof to said cylinder chamber and valve means carried by said rotor means to provide a structure for one way fluid flow through said opening to said cylinder chamber.

References Cited in the Ille of this patent UNITED STATES PATENTS 626,996 Hall June 13, 1899 1,152,729 Hele-Shaw Sept. 7, 1915 1,172,412 Von Saalfeld Feb. 22, 1916 (Other references on following page) 

